Baricitinib is one of the first once-daily oral selective JAK1 and JAK2 inhibitors for the treatment of rheumatoid arthritis (RA). Image courtesy of Patti Adair.
Baricitinib inhibits the activity of the selective JAK1 and JAK2 enzymes, interfering with the JAK-STAT signalling pathway. Image courtesy of Ann Rheum Dis/NCBI.
RA causes the immune system to attack the body’s own tissues. Image courtesy of James Heilman, MD.

Olumiant® (baricitinib) is one of the first once-daily oral selective JAK1 and JAK2 inhibitors for the treatment of moderate-to-severe active rheumatoid arthritis (RA).

Discovered by Incyte, the drug’s development and commercialisation is handled by Eli Lilly under an exclusive worldwide licence and collaboration agreement signed in December 2009.

Under the deal, Incyte received milestone-based and global regulatory payments, including $35m for the submission of a new drug application (NDA) and $100m for the drug’s approval.

Eli Lilly submitted a new drug application (NDA) for baricitinib to the US Food and Drug Administration (FDA) in January 2016. Olumiant® secured the FDA’s approval in June 2018.

The drug received marketing authorisation in Europe in February 2017, while Japan’s Ministry of Health, Labor and Welfare (MHLW) granted marketing approval in July of the same year.

Rheumatoid arthritis

RA is an autoimmune disease characterised by inflammation, pain, swelling, stiffness, loss of function and gradual destruction of joints. It can affect any joint, but most commonly affects those in the wrist and fingers. The disease can affect other body parts such as the eyes, mouth and lungs.

RA often starts in middle age and is most common in older people. Genetics, environmental conditions and hormone activity are all factors in the likelihood of developing the condition.

Olumiant’s mechanism of action

Olumiant® is a Janus kinase (JAK) inhibitor that functions by inhibiting the activity of selective JAK1 and JAK2 enzymes, which interfere with the JAK-STAT signalling pathway.

Cytokines play a major role in regulating cell growth and immune response. They bind and activate type I and type II cytokine receptors, which depend upon the JAK enzymes for signal transduction.

JAK inhibitor drugs prevent the activity of the JAK enzymes and JAK phosphorylate-activated cytokine receptors and block the cytokine signalling.

Phosphorylated cytokine receptors produce signal transducers and activators of transcription (STAT) factors, modulate gene transcription and inhibit immune-pathogenesis.

Olumiant® is available as oral, light pink, oblong, debossed, film-coated, immediate-release tablets. The recommended dose is 2mg once daily.

Clinical trials on Olumiant

The NDA was submitted to the FDA based on results obtained from Phase III clinical trials RA-BEACON in December 2014, RA-BUILD in February 2015, RA-BEGIN in September 2015 and RA-BEAM in October 2015.

The FDA’s approval was based on the positive outcomes of the RA-BEACON study.

RA-BEACON included 527 RA patients that showed inadequate responses to traditional disease modifying anti-rheumatic drugs (DMARD). The primary endpoint of the study was ACR20 response rates at week 12.

Approximately 49% of patients treated with Olumiant® showed higher ACR20 responses compared to 27% of placebo-treated patients. The drug provided early symptom relief after the first week and showed significant improvement in physical function compared to those on placebo.

RA-BUILD included RA patients that did not show any distinct response to biological therapies. The study included patients that had a defined or no prior treatment with methotrexate and were unaware of other traditional or biological DMARDs.

Aimed to evaluate baricitinib’s safety and efficacy, RA-BUILD enrolled approximately 600 patients that were randomised to one of the three study arms: once-weekly oral methotrexate monotherapy, 4mg once-daily oral baricitinib monotherapy or 4mg once-daily baricitinib in combination with once-weekly oral methotrexate.

“The FDA’s approval of the drug was based on the positive outcomes of the RA-BEACON study.”

The trial demonstrated non-inferiority of baricitnib monotherapy to methotrexate monotherapy based on ACR20 response after 24 weeks of treatment. Baricitinib was found to be superior to methotrexate based on the ACR20 response.

RA-BEAM was conducted to demonstrate the safety and efficacy of baricitinib along with methotrexate in RA patients, compared to a placebo for 24 weeks or adalimumab for 52 weeks. It enrolled more than 1,300 patients that were randomised to 4mg oral-once daily baricitinib with methotrexate or 40mg injectable every other week, adalimumab with methotrexate or placebo with methotrexate.

The trial demonstrated baricitinib’s superiority over placebo after 12 weeks and 24 weeks based on the ACR20 response in preventing the progressive radiographic structural joint damage.

Baricitinib was also found to be superior to adalimumab in demonstrating response and improvement in DAS28-hsCRP score (disease activity score calculator in RA patients) after 12 weeks. The benefits of treatment with baricitinib were observed and evaluated at 12, 24 and 52 weeks of therapy.

The fifth phase three study on baricitinib took place in China in 2014. This trial included patients that were naive to methotrexate, inadequate responders to methotrexate, conventional DMARDs or tumour necrosis factor (TNF) inhibitors.

Related Projects